Clock Speed

What Does Clock Speed Mean?

Clock speed is the number of cycles per second produced by a crystal oscillator, which regulates the timing for a synchronous circuit, such as a CPU. Clock speed is measured in megahertz (MHz) or gigahertz (GHz).


The clock speed cycle of a CPU is a repetitive variation of the high and low voltages sent to a crystal oscillator. This steady pattern creates a frequency that is regulated by the number of times the voltage goes from high to low. One cycle is usually less than a nanosecond. The CPU instructions are implemented during specific points of the wave. One full wave is known as the instructions per cycle (IPC).

Increasing CPU clock rate is one of several ways to improve the speed of information being processed.

Clock speed is also known as clock rate or clock frequency.

Techopedia Explains Clock Speed

A faster clock speed can speed up processing, but increasing the clock speed at an accelerated rate can sometimes be harmful to a PC, especially if other components are not upgraded. Depending on the CPU, it can process one or more instructions per clock pulse. Newer PCs can process more than one instruction per clock pulse and usually have a larger bus, which determines how fast data on the motherboard is moving.

References to the clock speed cycle are often synonymous to a fixed sinusoidal waveform, known as a sine wave or sinusoid. The cycles move between a logical 0 and a logical 1 state to make a full cycle. In order to achieve maximum clock rate and to function properly, the clock pulse needs to finish the current signal line before the next line can begin. The signal line transition cycles back and forth between 0 and 1. If the next signal starts too soon, the outcome will be inaccurate. The IPC is one of the many factors that affect CPU performance.

References to software benchmarks are usually the best way to compare different CPU families instead of referring only to clock rates.


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Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.